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. 1978 Jul;63(3):471–474. doi: 10.1111/j.1476-5381.1978.tb07799.x

Effect of labetalol on the uptake of [3H]-(-)-noradrenaline into the isolated vas deferens of the rat.

G M Drew, A Hilditch, G P Levy
PMCID: PMC1668086  PMID: 667491

Abstract

1 The effects of the combined alpha- and beta-adrenoceptor blocking drug, labetalol, on the uptake of [3H]-(-)-noradrenaline into the isolated vas deferens of the rat have been determined and compared with those of some other alpha-adrenoceptor blocking drugs and cocaine. 2 Labetalol, like cocaine, produced a simple competitive inhibition of [3H]-(-)-noradrenaline uptake and was about 4 times less potent than cocaine. It is concluded that labetalol is a potent inhibitor of uptake1. Phentolamine and thymoxamine also inhibited [3H]-(-)-noradrenaline uptake, and were respectively 8 and 14 times less potent than cocaine. Tolazoline, piperoxan and yohimbine were inactive in concentrations up to 30 microgram/ml. 3 The uptake1 blocking action of labetalol could explain, at least in part, the previously reported difference in its ability to block noradrenaline and phenylephrine vasopressor responses in the anaesthetized dog. 4 The possibility that uptake1 inhibitory concentrations of labetalol could be present in the blood of subjects receiving normal antihypertensive doses of the drug is discussed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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